1. Field of the Invention
The invention generally relates to a knob structure, and more particularly to a knob structure which creates a feeling of segments when turns.
2. Description of the Related Art
Taiwan patent No. I254957 (publication date: May 11, 2006) discloses an electronic device with a knob structure includes a casing with the knob structure thereon. The knob structure includes a first turning element having a first protrusion; a second turning element connecting to the first turning element in a way that the first turning element turns as the second turning element turns; a moving element which moves between the first and second turning elements and has a second protrusion matching the first protrusion for stopping the moving element in a idle position; and an elastic element which locates between the moving element and the second turning element and is used to return the moving element to the idle position by apply an elastic force. When the first turning element turns, the moving element moves due to the relative movement of the first protrusion and the second protrusion. When the first turning element stops working and the moving element returns to the idle position, the first protrusion substantially engages with the second protrusion.
In the conventional knob structure above, the relative movement of the first protrusion of the first turning element and the second protrusion of the moving element creates a feeling of segments. However, great contact area between the first protrusion and the second protrusion forms great friction in operation. Furthermore, the first turning element and the moving element are both made of plastics which would form plastic scraps due to the frictional operation.
Therefore, there is a need of an improved knob structure which solves the above problems. The inventors have intensively studies over the need and finally provide a new knob structure which overcomes the prior disadvantages.